Telecommunication service providers use a variety of techniques to troubleshoot faults occurring in systems that use a copper twisted-pair telephone line (also referred to here as a “local loop”). Typically, a fault such as an open circuit or a short circuit in a local loop is found using either a handheld testset or by a mechanized metallic loop test (MLT) system. These devices are normally able to measure the distance from the test device to the loop fault. In some situations, this approach can reduce the circuit restoral time as well as associated labor cost.
Although nearly all plain old telephone service (POTS) circuits are attached to such an MLT system, a large number of fielded high speed digital subscriber line (HDSL) circuits are not. These HDSL circuits include HDSL, HDSL2, and HDSL4 circuits, which are also collectively referred to here as “HDSLx” circuits. These HDSLx circuits typically carry critical DS1 data and have mean-time-to-restoral (MTTR) times that are typically subject to service level agreements. Returning these HDSLx circuits to service quickly after a fault is typically a high priority for service providers.